16-Foot Transonic Tunnel
|Center:||Langley Research Center|
|Historic Eligibility:||National Register Eligible|
|Important Tests:||B-58 Hustler, F-14 Tomcat, F-15 Eagle, F-18 Hornet, B-1 Bomber, Apollo Moon Mission Spacecraft, NATF, HiMAT|
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In the late 1930s, the Special Committee on Future Research Facilities proposed the construction at Langley of a wind tunnel with a 16-foot diameter test section that could evaluate the cowling and cooling of full-sized aircraft engines and propellers. Approval for construction was granted in 1939, and the new 16-Foot High Speed Tunnel (HST) became operational in November 1941 and began testing on December 5, 1941, just two days before the Japanese attack on Pearl Harbor. Later in the war, in addition to engine cooling work, testing focused on wing/aileron/elevator flutter problems and bomb/bomb fuse aerodynamics (possibly including the first atomic bombs according to several sources).
While the 16-Foot HST was never Langley's largest or fastest wind tunnel, it did play an important role in the postwar evolution of tunnel design. In the late 1940s, Langley physicist Ray H. Wright observed that the interference caused by wind tunnel walls could be minimized by placing slots in the test section throat, a concept that came to be known as "slotted throat" or "slotted wall tunnel" design. Testing this new design in the 16-Foot HST, Langley engineers found that it allowed for transonic speeds (up to and beyond the speed of sound, Mach 1, approximately 761 mph at sea level). Retrofitted with a new slotted test section throat and re-powered to 60,000 hp, the facility was re-designated the 16-Foot Transonic Tunnel (TT) in December 1950. Work on the slotted test section in the 16-Foot HST was instrumental in Langley winning the Collier Trophy in 1951. In 1961, a revision of the Langley 16-Foot Transonic Tunnel added a compressor driven by a 36 000 hp motor. This compressor removed about 4.5 percent of the tunnel mass flow from the test section and surrounding plenum and exhausted it to the atmosphere. The wind tunnel with this test-section air removal system was placed in operation on March 9, 1961 and a maximum test-section Mach number slightly greater than 1.30 was achieved.
The 16-Foot TT remained an important test facility through the Cold War era and beyond, with virtually every military airplane design undergoing testing in the tunnel. A partial list of these aircraft include the B-58 Hustler, F-100 Super Sabre, F-111 Aardvark, F-14 Tomcat, F-15 Eagle, F-18 Hornet, C-5 Galaxy, F-117 Nighthawk, B-1 Lancer, B-2 Spirit and X-45 UCAV, as well as the Apollo/Saturn moon mission spacecraft, the Space Shuttle, and the Boeing X-40 (test vehicle for the USAF X-37 Reusable Launch Vehicle). The tunnel also supported experimental programs such as the X-1, X-15, Highly Maneuverable Aircraft Technology (HiMAT) and the Joint Advanced Strike Technology (JAST). Rehabilitation efforts in 1969, 1977, and 1989-90 kept the 16-Foot TT equipped with state-of-the-art testing facilities, but with the end of the Cold War, NASA was faced with a surplus of tunnels across the country. Under the Wind Tunnel Enterprise program established in 1994, the 16-Foot TT provided testing facilities to clients in private industry such as Boeing, covering its $10 million annual operating budget with customer fees. NASA finally closed the facility in 2004.
During the long history of the 16-Foot Transonic Tunnel, the tunnel staff managed several other test facilities that added significantly to its test capabilities. These test facilities included:
- Outdoor static (no external flow) engine/propeller test stand. Photographs indicate that this existed as early as 1943.
- Annular Transonic Tunnel. This facility was based on the “whirling arm” concept and was located in Building 1234 from 1947 to 1952.
- Small circular “parasite” test sections. These parasite sections operated at speeds up to Mach 1.6 by sucking outside air through a long diffuser into the low-pressure test section of the 16-Foot HST. The Collier Trophy winning slotted test section was first proved to work in one of these test sections in 1947. (Photos)
- Jet Exit Facility (JETF). After the Annular Transonic Tunnel was removed and piston engines were mostly superseded by jet engines, Building 1234 housed the JETF where jet nozzle designs were researched. Much of the nonaxisymmetric (2-D) nozzle and thrust vectoring nozzle technology used on many current military aircraft was developed in this facility. The facility was demolished in 2011.
- 4 x 4-Foot Supersonic Pressure Tunnel. Around 1970, the 16-Foot Transonic Tunnel staff became responsible for the operation of this supersonic tunnel that was located beside the 16’TT drive control building. This capability allowed 16’TT staff to test vehicles such as the F-14 Tomcat and F-15 Eagle throughout their entire subsonic/transonic/supersonic flight envelope. The last research run in the facility was made on a Single-Engine High-Pressure Air Nacelle Model on September 2, 1976 and the "official" tunnel retirement date was September 3, 1976. The 4 x 4-Foot Supersonic Pressure Tunnel was decommissioned in 1977 and later demolished; the National Transonic Facility (NTF) was later built on the site.
- 16- by 24-Inch Water Tunnel. To provide a cheap capability for flow visualization over complex configurations, the 16’TT staff operated a water tunnel in Building 1234 during the 1980’s and 1990’s. True to the 16’TT mission, models tested in the facility could simulate inlet and exhaust flows. This facility was demolished sometime in the 1990’s.
The 16-Foot tunnel circuit was demolished in 2011. This map and aerial show the various components of the facility. The only remaining structure is the brick office building, 1146. Click here to see the new homes for salvaged items.
[top] Aero Projects
In late 1941, the first test in the 16-Foot High Speed Tunnel was initiated on the Douglas XA-26 Invader configuration. This airplane was a twin-engine (Pratt & Whitney R-2800 Double Wasp engines), light attack bomber that saw service in World War II and several cold war conflicts. The first flight was on July 10, 1942.
The photograph shows the first head of the 16-Foot High Speed Tunnel, Mr. Dave Bierman, standing next to a XA-26 full-scale engine/nacelle/propeller/stub-wing section mounted in the tunnel. The purpose of the test was to evaluate engine cooling and exhaust performance.
The first traditional “aerodynamic” test on a complete model was conducted during 1944 on the Convair B-36 Peacemaker configuration. This strategic bomber aircraft was powered by six engines with pusher propellers and was the largest mass-produced piston engine aircraft ever made. The first flight was on August 8, 1946 and the airplane was operational from 1949 to 1959.
The photograph shows a complete B-36 aerodynamic model mounted upside down in the 16-Foot High Speed Tunnel test section. Several aerodynamic flutter tests, one on the Vought SB2U-2 Vindicator aileron in 1942 and one on the Grumman TBF Avenger horizontal tail/elevator in 1943, were conducted prior to the B-36 test, but the B-36 test was the first force and moment aerodynamic test on a complete configuration. Except for these tests, all prior testing in the 16-Foot High Speed Tunnel had been propulsion related (cooling, exhaust design, propeller performance, etc.)
The Bell X-1 was the first of the so-called X-planes designated for testing new technologies and was tested in the 16 Foot Tunnel during 1951. The aircraft was a joint NACA-U.S. Army Air Forces/US Air Force supersonic research project to break the “sound barrier”. The aircraft first flew on January 19, 1946 and on October 14, 1947 the X-1 became the first aircraft to exceed the speed of sound during controlled level flight.
The photograph shows a X-1 sting-mounted aerodynamic model mounted in the 16-Foot Tunnel test section. Since transonic wind tunnel testing was not possible until the development of the slotted test section (see separate panel on this subject), this model was tested about 5 years after the first flight of the X-1. These tests were used to study vehicle aerodynamics encountered during flight in a controlled steady-state environment and also to validate the new slotted test section experimental results.
The P.1127 was the developmental aircraft that led to the Hawker Siddeley Kestrel and Harrier, the first vertical take-off and landing (VTOL) jet fighter-bomber. Hover flight with the P.1127 was achieved in Nov. 19, 1960, first conventional take-off and landing was made on July 7, 1961 and the first transition from vertical to forward flight occurred on Sept. 8, 1961. The configuration was tested in the 16-Foot Transonic Tunnel during April/May 1960 with two additional tunnel entries occurring in Sept. 1960 and June 1961. The Boeing AV-8B Harrier II, a direct descendant of the P.1127, was tested in the facility during Dec. 2001 and April 2002 as part of the Abrupt Wing Stall Program.
The photograph shows the P.1127 sting mounted in the 16-Foot Tunnel test section. This is one of the only models ever known to have been tested with both inlet flow and hot exhaust flow simulated. The 16-Foot Tunnel staff pioneered the technique of hot exhaust testing utilizing hydrogen peroxide jets.
The F-111 medium range fighter-bomber was the first variable-sweep wing production aircraft. The first flight was in Dec. 1964 and the aircraft entered service in July 1967. The F-111 was the most heavily tested airplane in the history of the 16-Foot Transonic Tunnel with 19 entries during 1963 to 1968 (581 occupancy days). These tests resulted in substantial changes to the F-111 afterbody and nozzle design. Tests were conducted on an isolated nozzle model, a 1/20-scale aerodynamics model (4 entries), a 1/12-scale propulsion model (10 entries), a 1/6-scale inlet model (3 entries), and a 1/16-scale blockage model.
The photograph shows the 1/12-scale propulsion model with wings swept aft mounted in the 16-Foot Transonic Tunnel. This model, with working (aerodynamically controlled as on airplane) nozzle blow-in-doors and flaps, a hot hydrogen peroxide primary exhaust, a high-pressure-air secondary nozzle flow, and a low-pressure-air nozzle boundary layer bleed, was one of the most complex ever tested in the facility.
The F-15 is considered one of the most successful modern air superiority fighters ever produced with over 100 aerial combat victories with no losses. F-15 design proposals were submitted in 1969, first flight occurred in July 1972, and the airplane entered service in January of 1976. The 16-Foot Transonic Tunnel (16’TT) contributions to the F-15 program started in 1969 with tests on the Republic F-15 proposal configuration and supplying a member (Bobby Berrier) to the F-15 contract Source Evaluation Board. Multiple wind tunnel tests on the winning McDonnell Douglas configuration were conducted during 1970 to 1972. These tests resulted in removal of ventral fins on the afterbody along with an increase in vertical tail height (to offset the loss in directional stability) that substantially reduced aft-end drag. The F-15 models were later utilized to develop nonaxisymmetric (2-D)/thrust vectoring nozzle technology during multiple tests from 1976 to 1988.
The photograph shows the .047-scale F-15 propulsion model (note the faired inlets) mounted on the “hockey stick” support system. The ventral fins on the afterbody were later removed as a result of tests in the 16-Foot Transonic Tunnel.
The Northrop Grumman B-2 Spirit (also known as the Stealth Bomber) is the first strategic heavy bomber with "low observable" stealth technology designed to penetrate dense anti-aircraft defenses and deploy both conventional and nuclear weapons. The B-2 originated from the Advanced Technology Bomber (ATB) black project that started in 1979. The Northrop/Boeing team's ATB design was selected over the Lockheed/Rockwell design on 20 October 1981. First flight occurred in July of 1989. Six tunnel entries (two during the competition phase prior to contract award) occurred in the 16-Foot Transonic Tunnel from1980 to 1983. Inlet airframe (four entries) and jet effects (two entries) models were tested under heavy security. Models were built up in the Jet Exit Facility (Bldg. 1234) behind the wind tunnel and moved under cover of darkness into the wind tunnel at times outside of Soviet satellite coverage. In addition, the built-up models included fake vertical tails and were covered with dark fabric.
The photograph shows the B-2 aircraft in flight. Because of ultra tight security at the time, all photos of the models tested in the 16-Foot Transonic Tunnel were removed from the facility and none exist in the NASA photo files.
The High Alpha Research Vehicle (HARV) is a modified McDonnell Douglas/ Northrop F/A-18 Hornet used by NASA for research at high angles of attack using thrust vectoring in the early 1990’s. The F-18 HARV and Rockwell-MBB X-31 (thrust vectoring systems of both aircraft also tested in the 16-Foot Transonic Tunnel Jet Exit Facility) were the first free-world aircraft to demonstrate multi-axis thrust vectoring for control at post-stall angles-of-attack. Both aircraft demonstrated stable controlled flight at an angle-of-attack of approximately 70 degrees. In addition to tests of the F-18 HARV thrust vectoring system in the Jet Exit Facility, the configuration spent 74 occupancy days in the 16-Foot Transonic Tunnel during 1991.
The photograph shows the F-18 HARV configuration mounted in the 16-Foot Transonic Tunnel at an angle of attack of 70 degrees. The model is mounted on a bifurcated support system that not only carries high-pressure air for the nozzle thrust vectoring system but also lets the wings (outboard section modified) rotate relative to the support system thus avoiding lengthy model support knuckle changes for high angles of attack.
The Lockheed C-5 Galaxy is one of the largest aircraft in the world. It was designed to provide strategic heavy airlift over intercontinental distances. The first flight was in 1968 and has been operational with the USAF since 1970. The proposed Lockheed C-5A configuration was first tested in the 16-Foot Transonic Tunnel (16’TT) during May of 1965 and the configuration was also tested in June 1971 as part of a wind tunnel correlation study. The C-5M Super Galaxy configuration with larger more powerful engines was tested in the 16’TT in October 2001.
The photograph shows a front view of the C-5M Super Galaxy mounted in the 16’TT for tests to determine the aerodynamic impact of new larger engines and redesigned engine pylons on aircraft performance. The engines are simulated with flow-through nacelles.
The Boeing X-45 unmanned combat air vehicle (UCAV) is a concept demonstrator for future combat aircraft that are able to complete combat missions, including weapons delivery, not only unmanned but completely autonomously. The first flight of the X-45A occurred in May of 2002. Developmental testing on the X-45A configuration was initiated in the 16’TT with three entries starting in October 1999 on inlet, aerodynamic and loads models. As the X-45 configuration evolved, test entries on the X-45B inlet occurred in September 2002 and on the X-45C inlet and aerodynamic models in August through November of 2003.
The photograph shows the X-45A UCAV aerodynamic model with a flow-thru inlet sting mounted in the 16-Foot Transonic Tunnel.
[top] Space Projects
The first space project tested in the 16-Foot Transonic Tunnel was on the Boeing X-20 Dyna-Soar. The X-20 was a United States Air Force program initiated in 1957 to develop a space plane that could be used for a variety of military missions. It could be boosted to earth orbit and then, unlike other space vehicles of the time such as the Mercury/Gemini capsules that would parachute to earth, fly back to earth and land like an airplane much like the later Space Shuttle. The program was eventually canceled in December 1963.
The photograph shows the sting mounted aerodynamic model of the X-20 Dyna-Soar model. This model was smaller than most models tested in the 16-Foot Tunnel; it was apparently built so that the same model could also be tested in smaller supersonic wind tunnels.
On July 20, 1969, the Saturn launch vehicle carried the Apollo Command, Service and Lunar Excursion Modules to the moon and successfully landed the first humans on its surface fulfilling John F. Kennedy’s national goal of “landing a man on the moon by the end of the decade”. Tests in the 16-Foot Transonic Tunnel on the Apollo Escape System and the Saturn nozzle hinge moments were both initiated in 1962. The performance of the escape rocket (utilizing hydrogen peroxide hot jets), a check for jet plume impingement on the Command Module, and the aerodynamic interaction between the Command and Service Modules during separation were studied during 5 additional tunnel entries between 1963 and 1964. In addition, Service Module panel flutter characteristics were studied during 1964 and 1968 tunnel entries.
The photographs show the Apollo command module/service module separation model and Saturn rocket hinge-moment model in the 16-Foot Transonic Tunnel. Both models used hydrogen peroxide hot jets to simulate rocket exhausts.
The Space Shuttle, part of the Space Transportation System (STS), was the American spacecraft operated by NASA for human orbital spaceflight missions from 1982 to 2011. At launch, the STS consists of the Space Shuttle, a large external fuel tank, and two solid rocket boosters. Although the Space Shuttle conducted many missions, it is best known for the deployment and later repair of the Hubble Space Telescope, and the delivery of personnel and supplies to the International Space Station. The Space Shuttle attitude probe was tested in the 16’TT in March 1976. Eight more Shuttle entries occurred before the end of 1984 for a total of 133 occupancy days in the 16’TT studying orbiter and ascent configuration aerodynamics, external tank loads, and reaction control system and tile aerodynamics.
The photograph shows the Space Shuttle ascent configuration (shuttle rockets firing while solid rocket booster motors are still firing) in the 16-Foot Transonic Tunnel. Solid wood plumes are used to simulate rocket exhaust flow from both vehicles. This model was used to study the aerodynamic interactions between the shuttle, external fuel tank and solid boosters during ascent.
In his 1986 State of the Union speech, President Ronald Reagan announced plans for a new vehicle, called the “Orient Express”, that would be able to cruise at hypersonic speeds (Mach 25) and fly to Tokyo in 2 hours. This announcement was based on a Defense Advanced Research Projects Agency (DARPA) project called Copper Canyon that was started in 1982 to develop a single-stage-to-orbit spacecraft. After the announcement, industry airframe and engine companies, and government agencies (including NASA) initiated the National Aerospace Plane (NASP) program to develop the technologies necessary for a hypersonic vehicle designated X-30. Amid budget cuts and technical difficulties, the program was canceled in 1993. Six Copper Canyon/NASP tunnel entries were completed in the 16’TT between 1984 and 1993. Hypersonic technology development in the 16’TT actually started prior to the NASP program with an air breathing launch vehicle study in 1974 and continued up to facility shutdown in 2004 with nine Pegasus/X-43 entries.
The photograph shows a front view of one of the early Copper Canyon NASP configurations mounted in the 16-Foot Transonic Tunnel. The configuration was a winged cone forebody/truncated cone afterbody with a ring of air-breathing supersonic combustion ramjets (or scramjets) completely circling the body.
Starting in 1996 and continuing until facility shutdown, approximately 13-percent of 16’TT test time was devoted to the development of reusable space planes. In actuality, this technology started even earlier in the facility with tunnel entries of the X-20 Dyna-Soar in 1960 (highlighted on another wall panel), and the X-24A and X-24B in 1973 but these efforts were not as concentrated as the effort starting in 1996. Starting in 1996, the X-33 (6 entries), X-34 (2 entries), X-38 (4 entries), X-40 (1 entry), Pegasus/X-43 (9 entries), Next Generation Launch Technology (1 entry), and Orbital Space Plane (3 entries) were tested in succession.
The photograph shows the X-34 aerodynamics model sting mounted in the 16-Foot Transonic Tunnel.
[top] Technology Development
In the late 1930s, the Special Committee on Future Research Facilities proposed the construction at Langley of a wind tunnel with a 16-foot diameter test section that could evaluate the cowling and cooling of full-sized aircraft engines and propellers. The new High Speed Tunnel (HST) was declared operational on December 5, 1941, just two days before the Japanese attack on Pearl Harbor, although testing on the Douglas A-26 (see highlight on another wall panel) actually started in November 1941. During World War II, the new tunnel was used to evaluate the cooling problems plaguing the air-cooled engines that powered virtually every U.S. fighter and bomber aircraft. Later in the war, testing focused on evaluating full-sized propellers and possibly the shapes of the first atomic bombs. The last propeller test entry occurred in 1953.
Unlike the other wall panels that emphasize models installed in the wind tunnel, this photograph shows a Curtiss XSC-1 Seahawk engine mounted outside on a ground stand for static tests (also tested in the HST). This is a reminder that the 16-Foot facility has always had an associated static test facility for engine, propeller and nozzle performance tests. The most recent static test facility, the Jet Exit Facility located in building 1234, was demolished in 2011. Over its history, tunnel branch staff also operated the 4- by 4-Foot Supersonic Pressure Tunnel (located at the current NTF tunnel site) and a water tunnel in building 1234.
In 1947, based on theoretical results, a team of researchers in the 16’ High Speed Tunnel (HST) became the first to be involved in developing a slotted-throat tunnel. A circular 10-slot test section was tested in a small “parasite” wind tunnel connected to the low-pressure test chamber of the 16’HST. With no model installed, the flow in this “parasite” tunnel easily went through the speed of sound. In the fall of 1947, it was decided that the 16’ HST would be converted to a slotted test section and in the spring of 1948, it was decided to also convert the 8’ HST. The 8’ HST began regular transonic operation on October 6, 1950 and just two months later, the renamed 16-Foot Tunnel also became operational with a slotted test section. In 1951, John Stack (Division Chief) and Associates at Langley Aeronautical Laboratory, NACA received the Collier Trophy for the conception, development, and practical application of the transonic wind tunnel throat.
The photograph shows the 16-Foot Tunnel with the newly installed slotted wall test section. The installed model is the 120” drop body, which was the first model, tested in the new test section. This model was used to compare with flight data (from drop tests) to check for tunnel blockage/wall interference effects at transonic speeds near Mach 1.
Efficient cruise at subsonic and supersonic speeds dictates wing designs at two extremes; low wing sweep, high aspect ratio at subsonic speeds and high wing sweep, low aspect ratio at supersonic speeds. The obvious solution is a variable sweep wing. Unfortunately, previous attempts to apply this concept also required a forward translation of the wing to offset a significant nose down pitching moment generated as the wing was swept aft. Such a complex and heavy mechanism was judged unpractical for operational aircraft. The practical variable sweep wing is generally acknowledged to be a Langley innovation (with the help of Barnes Wallis from England) developed during the Tactical Aircraft (TAC) Program. The innovation was to move the wing pivot point well outside the airplane centerline. This innovation was responsible for the successful utilization of variable sweep wings on the F-111, F-14, and B-1 aircraft. Eleven variable sweep wing models, including the British “Swallow” bomber model; McDonnell, Republic and Convair TAC models; and the Langley TAC VIII model, were tested in the 16’TT between 1959 and 1962.
The photograph shows the British “Swallow” bomber propulsion model installed in the 16-Foot Tunnel. This configuration was designed by Barnes Wallis from England (of bouncing “dam buster” bomb fame) and not only had variable sweep wings but also utilized multiaxis thrust vectoring nozzles for aircraft control (the design had no conventional aerodynamic control surfaces).
From the first day to the last day of operation, the 16-Foot Transonic Tunnel was at the forefront of integrating the propulsion system (engine/propeller/nozzle/inlet) with the airframe (wing/fuselage/empennage). In addition to full-scale piston engine installations (and one full-scale jet engine installation in 1963), the 16’TT staff perfected propulsion simulation techniques such as hydrogen peroxide hot-jet simulation (first used in a Grumman F11F test in 1955) and high-pressure air cold-jet simulation (first used in 1965) for use in subscale models. The research programs conducted in the facility provided propulsion/airframe integration (PAI) design guidelines widely used by industry during aircraft development programs. As aircraft designs matured, PAI models of most military aircraft were eventually tested in the facility; these tests resulted in major modifications to many of these aircraft such as the P.1127, F-101, F-11F, A-6, F-111, F-14, F-15, B-1 and B-2.
The photograph shows a generic high-pressure-air twin-engine propulsion/ airframe integration model mounted in the 16-Foot Transonic Tunnel on a bifurcated support system. In-house research programs like this provided design guidelines to industry on issues such as tail placement, nozzle and interfairing design, nozzle spacing, jet effects, etc.
The 16’TT was the primary developer of 2-D nozzle and thrust vectoring technology in the free world. Although round nozzle thrust vectoring was tested in 1959 (Swallow model) and 2-D thrust vectoring nozzles in 1969 (wing-jet interference deflected jet model), development of these technologies did not start in earnest until 1974 with 2-D thrust vectoring nozzle exploratory tests. Between 1974 and 1994, over 75 16’TT entries (and a similar number in the 16’TT Jet Exit Facility) were made on NASA/DOD/Industry 2-D and/or thrust vectoring nozzles (either isolated or installed). In 1975, a Joint DOD/NASA/Industry Workshop, initiated by Branch management, was held at Langley and eventually produced a national NASA/DOD plan for the development of these technologies. An important part of this plan was the development of concepts for flight-testing thrust vectoring 2-D nozzles. Development of a three surface F-15 modified with canards and thrust vectoring 2-D nozzles was initiated by the 16’TT Branch with a contract to McDonnell Douglas in 1977. This configuration (designated the F-15 STOL and Maneuvering Technology Demonstrator) was eventually flight tested by the USAF in 1988. Other flight systems that were partially developed in the 16’TT and/or its associated Jet Exit Facility were the F-14 with yaw vanes, F-18 HARV, X-31, B-2, and F-35.
The photograph shows the F-15 S/MTD (STOL and Maneuvering Technology Demonstrator) propulsion model installed in the 16-Foot Transonic Tunnel. This configuration is an F-15 modified with 2-D thrust vectoring nozzles and a canard.
Inlet testing in the 16’TT started in 1961 with a test on the Hawker Siddeley P.1127 configuration and continued with tests on the F-111, RF-111, B-2, Naval Advanced Tactical Fighter (NATF), and Advanced Attack (AX) aircraft configurations. Research programs on natural laminar flow inlets, subsonic transport inlets, Advanced Transonic Transport (ATT) inlets, 2-D/military fighter inlets, and High Speed Research (HSR) inlets were also conducted prior to 1995. However inlet development testing started in earnest in 1995 when 16’TT managers decided to develop the hardware and skills necessary to be a world-class provider of inlet performance testing. Between 1995 and 2004, 17 inlet test entries were completed in the facility including tests on Advanced Short Take-Off/Vertical Landing (ASTOVL), Joint Advanced Strike Program (JAST), T-45, X-45B, and X-45C inlet configurations. In addition, research programs on advanced low-observable inlets, top-mounted inlets, and shape-memory-alloy controlled inlets were conducted during this period.
The photograph shows the Smart Aircraft and Marine System Projects Demonstration (SAMPSON) Smart Inlet installed in the 16-Foot Transonic Tunnel. This model was a full-scale F-15 inlet modified with shape memory alloy actuators to vary cowl lip angle and bluntness.
At least 2 different publications indicate that the original atomic bomb shapes were tested in the 16’ HST. Unfortunately, the tunnel logs during this time period have not been found and no photographs are in the 16’TT files to support this claim. Known technologies/test techniques in the tunnel resume include: 1943: Flutter/buffet testing 1944: Remotely guided bomb 1945: Bomb and fuse aerodynamics 1946: Aft and forward swept wings 1947: Advanced controls 1952: Free-to-Roll models 1954: Pulsejet 1954: Tethered free-flight model 1955: H2O2 hot jet testing 1957: Guided missiles 1957: Ballistic rockets 1960: Nuclear powered bomber 1962: Nuclear reentry vehicles 1962: Supersonic transport 1963: J85 turbojet tip-turbine fan 1965: Wing end plates (winglets?) 1965: High-pressure air jet testing 1968: Supercritical wing 1980: LO technology 1980: LDV flow-field measurements 1998: Joined wing 1998: Pressure sensitive paint
The photograph shows Mr. Bobby Berrier, one of the last Branch Heads of the 16-Foot Transonic Tunnel (1989-1997), standing in front of the RPV Smart Vehicle model which was used to investigate a variety of advanced aircraft control concepts.
It should be noted that some of the information contained herein on specific flight vehicles was obtained from Wikipedia.
[top] Equipment and Instrumentation
[top] Posters and Displays
[top] Unidentified or Special Purpose Models
[top] Personnel and Social Events
[top] 16-Foot Transonic Tunnel Models in Other Facilities
Langley Awarded Minute Man Flag 1952 tour of Center
The following stories and assorted tid-bits have been compiled so that the reader can get a feeling of some of the culture that existed in the facility. This culture not only existed at the 16-Foot Tunnel but also at the Langley Research Center. Some of the stories may sound sophomoric and even bordering on hazing by today’s standards but I firmly believe that these activities bonded 16’TT personnel together into a cohesive team that laughed, partied, and worked together without regard to position or status and with respect for everyone. I cherish these times and look back on them as some of the best years of my life. I think you could ask any “16-footer” and they would tell you that they loved the tunnel, the people, and the work at 16-Foot. (Bobby Berrier)